Fix: return the correct index when duplicates in binary_search

[torres446n]

Fixes #13886

Describe your change:

This pull request fixes the behavior of the binary_search algorithm when the input list contains duplicate elements.

Previously, the algorithm returned the middle duplicate index instead of the first occurrence of the target value.
This implementation modifies the loop logic so that the search continues to the left whenever a match is found, ensuring the first index is returned.

Example of the fix:

binary_search([1, 2, 2, 2, 3], 2)
# Before: 2
# Now: 1

• Add an algorithm?
• Fix a bug or typo in an existing algorithm?
• Add or change doctests? -- Note: Please avoid changing both code and tests in a single pull request.
• Documentation change?

Checklist:

• I have read CONTRIBUTING.md.
• This pull request is all my own work -- I have not plagiarized.
• I know that pull requests will not be merged if they fail the automated tests.
• This PR only changes one algorithm file. To ease review, please open separate PRs for separate algorithms.
• All new Python files are placed inside an existing directory.
• All filenames are in all lowercase characters with no spaces or dashes.
• All functions and variable names follow Python naming conventions.
• All function parameters and return values are annotated with Python type hints.
• All functions have doctests that pass the automated testing.
• All new algorithms include at least one URL that points to Wikipedia or another similar explanation.
• If this pull request resolves one or more open issues then the description above includes the issue number(s) with a closing keyword: "Fixes #ISSUE-NUMBER".